PELVIS MINOR 481 



plane to form the medial pubo-vesical ligaments. Those liga- 

 ments having been recognised, the finger should be carried 

 laterally and then backwards between the wall of the pelvis and 

 the urinary bladder as far as the lateral border of the broad 

 ligament. The dissector will find he can do this quite easily, 

 and by doing it he will demonstrate the fact that between the 

 anterior border and infero -lateral surfaces of the bladder and the 

 wall of the pelvis there is a space filled with easily displaced 

 extra-peritoneal fat ; it is the lower and anterior part of the 

 so-called cave of Retzius, and it is bounded below by a layer of 

 fascia called the visceral pelvic fascia which extends from the 

 side wall of the pelvis to the pelvic viscera. The finger should 

 now be passed still farther backwards along the side wall of the 

 pelvis, beyond the lateral border of the broad ligament, until the 

 front of the hypogastric artery is reached ; but little resistance 

 will be met, and the dissector will be able to satisfy himself 

 that the lower part of the so-called cave extends round the 

 sides and front of the pelvis from the hypogastric artery 

 of one side to the corresponding vessel of the opposite 

 side. The upper part of the cave lies behind the anterior 

 abdominal wall, extending upwards between the inferior epi- 

 gastric arteries to the level of the umbilicus. The cave is of 

 practical importance, because, on account of the laxity of its 

 fatty contents, urine escaping from a ruptured urinary bladder, 

 or effused blood, or inflammatory exudations, can spread rapidly 

 throughout the area ; moreover, it is an area in which the 

 surgeon can readily separate the pelvic contents from the pelvic 

 wall. Having satisfied himself as to the presence and the 

 boundaries of the cave, the dissector should carefully remove 

 the extra-peritoneal fat which lies between the urinary bladder 

 and the wall of the pelvis minor, taking care to avoid injuring 

 any vessels which may be passing through the fat. When he 

 has completed this part of the dissection he will have displayed 

 on the side wall of the pelvis the following structures : The 

 obliterated umbilical artery, lying a short distance below the 

 level of the pelvic brim ; the obturator nerve, below the liga- 

 ment ; and, at a still lower level, the obturator artery and vein. 

 Passing from the umbilical artery to the bladder, the superior 

 vesical artery will be found. Lateral to the obturator vessels 

 and nerve, the parietal pelvic fascia will be seen ; and at the 

 bottom of the space he will find the visceral layer of the pelvic 

 fascia passing medially from the parietal layer to the bladder. 

 Just to the lateral side of the junction of the lateral border with 

 the posterior border of the urinary bladder he will find the lower 

 end of the ureter, and, if he passes a finger into the vagina, he 

 will recognise that the lower end of the ureter is crossing a recess 

 of the vagina, at the side of the lower end of the uterus, which is 

 called the lateral fornix of the vagina (Fig. 228). If the lower 

 border of the broad ligament is now carefully raised, the uterine 

 artery will be found passing medially above the ureter to the 

 side of the uterus (Fig. 227). 



Having displayed the structures in front of the broad liga- 

 ment, the dissector should turn to the posterior part of the 

 pelvis, where he must carefully divide the peritoneum along 

 the back of the lower border of the broad ligament, and then 

 turn the membrane behind the incision medially from the side 

 VOL. II 31 



